The invention relates to medical devices and can be used in cardiac surgery for replacement of the diseased native aortic and mitral heart valves in humans. This invention can also be successfully used for replacement of the diseased tricuspid valve.
There is a certain heart valve prosthesis [1] comprising an annular housing with fixing elements restricted by support surfaces facing the direct and reverse blood flow and a side surface facing the central axis of the housing, and leaflets mounted within the annular housing with the possibility to pivot between an open position, which allows the passage of the direct blood flow, and a closed position which restricts the blood backflow, each leaflet has an outer side surface having projections with support surfaces facing the direct blood flow, which interact with the corresponding support surfaces of said fixing element of the housing, a coaptation surface interacting with the corresponding coaptation surface of the other leaflet in the closed position, with projections having support surfaces facing the blood backflow and interacting with the support surface of the fixing element of the housing, an upstream and a downstream surfaces respectively facing the direct blood flow and the blood backflow, while the downstream surfaces of the leaflets have projections-cams which prevent the coaptation of the leaflets in the open position and restrict the opening angle of the leaflets.
This prosthesis, as experience of its clinical application had shown, has good hemodynamic characteristics and a small percentage of thrombotic and thromboembolic complications. However, its leaflets, which divide the hydraulic orifice of the housing into three segments, disrupt the homogeneous laminar structure of blood flow with creation of blood stagnation zones and thus preserving the possibility of thrombotic complications.
There is a certain heart valve prosthesis [2] comprising an annular housing, leaflets with the possibility to pivot and form a major zone of central passageway of the housing, and leaflet pivoting limiters. The leaflet pivoting limiters are represented by two pairs of projections located at the end surface of the housing facing the downstream blood flow, and which ensure limiting of their pivoting angle and permanent link with the housing by interacting with the side surfaces of the leaflets.
This prosthesis provides withdrawal of the leaflets from the housing orifice and therefore increases the homogeneousness of the flow structure. However the provision of the leaflet pivoting limiters at the end surface of the housing increases the prosthesis overall dimensions and risk of restriction of leaflet mobility by the internal heart structures.
This heart valve prosthesis was chosen by us as prototype prosthesis.
The objective of the proposed invention is to increase thromboresistance of prosthetic heart valve.